The present invention relates to a countercurrent extraction column for the liquid-liquid extraction of two phases which are not soluble in one another with simultaneous electrolysis, including a column in which an anode chamber is enclosed by a cathode chamber without the use of a diaphragm to separate the chambers.
Countercurrent liquid-liquid extraction columns with simultaneous electrolysis are known in which a cathode chamber is separated from an anode chamber by a diaphragm, i.e., a membrane made of a porous ceramic material. The use of a diaphragm gives rise to major disadvantages for such a column, such as, for example, the fact that the pores of the diaphragm can become plugged up during operation of the column. To overcome the problems caused by diaphragms, the prior art has provided countercurrent liquid-liquid extraction columns with simultaneous electrolysis without the use of diaphragms to separate an enclosed anode chamber from the cathode chamber. Columns of this type without diaphragms are used, among other purposes, to separate uranium-plutonium compounds by means of liquid-liquid extraction. Such a column is described in U.S. Pat. No. 3,869,374 to Goldacker et al, issued Mar. 4, 1975, which is hereby incorporated by reference. The column described in U.S. Pat. No. 3,869,374 is designed so that electrolysis and extractive separation can take place simultaneously therein. A light (organic) phase is charged into the bottom of the column and a heavy (aqueous) phase is charged into the top of the column. The heavy phase is discharged at the foot of the column and the light phase is discharged at the head of the column. The electrolytic reduction of plutonium and uranium takes place in the extraction column at a cathode which is positioned in the cathode chamber and which is made of fins radially attached to the bottom of a perforated plate.
In U.S. Pat. No. 3,869,374, communication between the anode chamber and the cathode chamber is provided by a plurality of bores which are directed either downwardly or upwardly from the horizontal. The anodes are arranged at the level of the bores and the cathodes are arranged directly above the bores. In one embodiment of the column of U.S. Pat. No. 3,869,374, the bores are provided in a nozzle which is mounted in the wall which separates the anode chamber from the cathode chamber, and, in a further embodiment, the bores are formed directly in the wall which separates the anode chamber from the cathode chamber.
Due to the relatively long current paths in the column described in U.S. Pat. No. 3,869,374, there results a relatively high cell resistance which leads to unduly high temperatures and a significant voltage drop across the electrolysis portion of the column.